Vex Replacement

[hcvcastro]

• browser: add initial IDialog class
• browser: add initial idialog.css
• browser: insert content to the dialog
• browser: use statics methods
• browser: simplify isVisible
• browser: rename 'show' -> 'open'
• browser: create dialog buttons
• browser: fix button type
• browser: initial CSS to buttons
• browser: add 'afterOpen' callback
• browser: add 'close' function
• browser: add button 'click' event listener